No I'm using the original cable. I took it apart, cleaned and inspected it and it looked in very good shape, then I lubricated it and reassembled it.
I think I may have locked-up the odometer when I turned it back to zero. Actually I turned it to 99999 and figured it would just roll over.
I think what's happening is the cable spins at transmission speed and activates the speedometer, then something binds in the odometer, then something in it "clicks" as it refuses to move. The wild behavior of the speedo must be the cable being torqued then released cyclically.